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STMicroelectronics L9777C13TR
- Part No.:
- L9777C13TR
- Manufacturer:
- STMicroelectronics
- Package:
- 12-LSOP (0.154", 3.90mm Width) Exposed Pad
- Datasheet:
-
L9777C13TR.pdf
- Description:
- IC REG LIN POS ADJ 600MA PWRSSO
- Quantity:
- Payment:
- Shipping:
Inventory:1,733
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Product details
Overview
L9777C13TR from STMicroelectronics is a monolithic low-dropout voltage regulator delivering up to 200 mA on VCC (5 V ±2%) and 50 mA on switchable VDD, with integrated watchdog, dual reset (NMI/RESET), adjustable undervoltage threshold, and automotive-grade thermal protection (−40 °C to 150 °C junction). It serves as the primary power supply and system supervision IC for engine control units and body electronics.
For engineers reviewing the L9777C13TR datasheet, L9777C13TR pinout, L9777C13TR application, or L9777C13TR equivalent, key selection considerations include its PowerSSO-12 package, VDD_EN-controlled tracking regulator, spike-dependent NMI filter timing, RESET/VDD_LOW dual-mode pin behavior (Option C), and 1 V minimum reset-sensing capability.
Technical Context
The L9777C13TR implements Option C functionality: VDD output is rated for 50 mA with ≤1.5 V dropout and short-circuit tolerance up to 40 V; the RESET pin functions exclusively as VDD_LOW, asserting low when VDD falls below (VCC − 300 mV) with spike-dependent filter time TFVDD; TIMING pin is unused and must be floated or grounded.
Its watchdog circuit uses external capacitor CD to set timeout window (TWOP–TWOL = 48 × TOSC), where TOSC depends on CD and internal 20 μA current sources; NMI asserts low on either VCC undervoltage (with adjustable threshold via RADJ) or watchdog timeout, and drives bipolar outputs with constant-current discharge for predictable fall time.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Output Voltage | 5.0 V ±2% - stable reference for MCU core logic under full automotive temperature and input range (5.6–31 V). |
| VCC Output Current | Up to 200 mA - sufficient for ASIL-B microcontrollers and peripheral drivers without external boost. |
| VDD Tracking Regulator | 50 mA max, ≤1.5 V dropout - supplies auxiliary circuits (CAN transceivers, sensors) with battery-short-tolerant operation up to 40 V. |
| Quiescent Current | 100 μA typ - enables always-on monitoring in sleep modes without excessive battery drain. |
| Reset Sensing Threshold | VDD_LOW asserts low when VDD < (VCC − 300 mV) - provides precise tracking-based fault detection for secondary rail integrity. |
| Operating Temperature | −40 °C to +150 °C TJ - qualified for under-hood automotive environments including engine control modules. |
| Watchdog Timeout | Configurable via CD capacitor - sets TWOP–TWOL window (e.g., 100 ms with 15 nF) for fail-safe MCU supervision. |
Pinout & Package
The L9777C13TR is housed in a PowerSSO-12 package with exposed die pad for enhanced thermal dissipation in high-power automotive applications.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | VDD_LOW (output) | Asserts low when VDD drops below (VCC − 300 mV); replaces double-reset function in Option C for dedicated VDD rail monitoring. |
| 2 | NMI (output) | Non-maskable interrupt output triggered by VCC undervoltage or watchdog timeout; bipolar driver with constant-current fall. |
| 3 | D (input) | External capacitor connection setting NMI filter time, watchdog oscillator period, and RESET delay; defines timing critical to safety response. |
| 4 | VDD_EN (input) | Active-high enable for VDD regulator; pulled down internally (10 μA) - requires explicit VCC tie for activation. |
| 5 | WD (input) | Watchdog pulse input; rising edge resets internal counter; missing edges within TWOP–TWOL trigger NMI assertion. |
| 6 | WD_EN (input) | Active-high watchdog enable; pulled down internally (10 μA) - disables WD function when low or floating. |
| 7 | VI (input) | Main battery input (5.6–31 V); supports short-to-40 V transient immunity per Option C design. |
| 8 | TIMING (NC) | No-connect in Option C; must be floated or grounded - unused due to removal of double-reset architecture. |
| 9 | VCC (output) | Primary 5 V regulated output (200 mA); accuracy ±2% across temp and line; requires ≥220 nF output capacitor. |
| 10 | VDD (output) | Tracking regulator output (50 mA); follows VCC minus fixed offset; requires ≥100 nF output capacitor. |
| 11 | GND | Power ground reference; connected to exposed die pad for thermal and EMI performance. |
| 12 | RADJ (input) | Adjusts VCC undervoltage threshold (0.7–0.96×VCC) via external resistor divider; tied to GND for default 0.94×VCC threshold. |
Key Features
| Feature | Design Value |
|---|---|
| VDD_SHORT_40V_TOLERANCE | Withstands 40 V transients on VDD pin - eliminates need for external TVS in 24 V commercial vehicle systems. |
| SPARK-DEPENDENT_NMI_FILTER | Filter time TRR shortens as VCC dip deepens - improves noise immunity while preserving fast response to catastrophic collapse. |
| VDD_LOW_TRACKING_MONITOR | VDD_LOW asserts at (VCC − 300 mV) with same spike-dependent timing as VCC - ensures coordinated rail integrity verification. |
| WD_SYNCHRONIZED_COUNTER | Each WD rising edge resynchronizes oscillator phase - reduces watchdog timing error to ±½ TOSC, critical for deterministic safety response. |
| UNDER_VOLTAGE_RESET_DOWN_TO_1V | NMI remains asserted as long as VCC > 1 V - guarantees reset signaling even during severe brownout conditions. |
Applications
| Engine Control Unit (ECU) | Body Control Module (BCM) |
|---|---|
Use Scenario: Real-time monitoring of 5 V MCU supply and 5 V CAN transceiver rail under wide battery fluctuation (6–16 V) and load dump (up to 40 V). IC Role / Device Role / Timing Role: Primary voltage regulator (VCC) and auxiliary rail supervisor (VDD_LOW); provides synchronized NMI reset and watchdog timeout with sub-100 μs response latency. Use Value: Enables single-chip power + safety supervision, reducing BOM count and PCB area versus discrete LDO + reset IC + watchdog solutions. | Use Scenario: Powering door module microcontrollers and LIN transceivers in ambient temperatures ranging from −40 °C to +105 °C. IC Role / Device Role / Timing Role: Supplies regulated 5 V (VCC) and tracks 5 V (VDD); monitors both rails with independent thresholds and delivers fail-safe NMI signal to host MCU. Use Value: Eliminates need for external reset delay RC networks and enables programmable watchdog timeout via single capacitor (CD). |
| Transmission Control Unit (TCU) | Advanced Driver Assistance System (ADAS) Camera ECU |
Use Scenario: Supporting ASIL-B compliant MCU operation with redundant voltage monitoring and watchdog supervision during gear-shifting transients. IC Role / Device Role / Timing Role: Delivers 200 mA VCC and 50 mA VDD with thermal shutdown at 150 °C; asserts VDD_LOW on VDD sag to trigger diagnostic logging before functional failure. Use Value: Meets ISO 26262 hardware fault tolerance requirements through integrated overtemperature, short-circuit, and undervoltage protection. | Use Scenario: Powering image sensor interface and ISP in compact rear-view camera modules exposed to under-hood thermal cycling. IC Role / Device Role / Timing Role: Provides stable 5 V (VCC) and tracks auxiliary 5 V (VDD); uses RADJ to lower reset threshold for extended low-voltage operation during cold cranking. Use Value: Extends operational envelope to 5.6 V input, enabling reliable startup during battery voltage sag without external boost circuitry. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar automotive voltage regulation and supervision applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLF35584QVVS1 | Higher integration: includes 3x LDOs, 2x DC/DC, window watchdog, and SPI diagnostics; no VDD tracking mode. | Targets complex domain controllers requiring multiple rails and functional safety reporting (ASIL-D capable). | Select when system demands multi-rail power management and ISO 26262 ASIL-D compliance - not drop-in for L9777C13TR's simpler topology. |
| MAX25210ATPA/V+T | Single 5 V LDO (300 mA) + independent watchdog + reset generator; no VDD tracking or VDD_LOW functionality. | Suitable for cost-sensitive ADAS sensors needing basic reset and watchdog, but lacks rail correlation features. | Choose for non-tracking applications where VDD supervision is handled externally - lower integration but smaller footprint and lower cost. |
Compared with TLF35584QVVS1 and MAX25210ATPA/V+T, the L9777C13TR uniquely combines VCC/VDD tracking regulation with correlated VDD_LOW monitoring and spike-adaptive filtering - making it optimal for cost-constrained, thermally demanding ECUs where rail interdependency is critical to fault detection.
Availability
L9777C13TR is available at Aetrix Electronics and suitable for engine control units, body control modules, transmission control units, and ADAS camera ECUs requiring stable component supply across automotive production lifecycles.
Supply support for L9777C13TR includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in automotive, industrial, and power management ICs with broad AEC-Q100 qualification coverage.
The L9777 belongs to ST's automotive power management and system basis chip (SBC) product line, designed specifically to consolidate voltage regulation, reset supervision, and watchdog functionality into a single robust device for engine and chassis control applications.
FAQ
What is the function of Pin 1 (RESET/VDD_LOW) in the L9777C13TR?
In L9777C13TR (Option C), Pin 1 operates exclusively as VDD_LOW - an open-collector output that goes low when VDD falls below (VCC − 300 mV) for a spike-dependent filter time. It does not provide traditional RESET functionality; NMI serves as the primary reset signal. This pin replaces the dual-reset architecture of Options A/B to dedicate supervision to the VDD rail.
Can the L9777C13TR be used without connecting an external capacitor to the D pin?
No - the D pin requires an external capacitor to define three critical timing parameters: NMI filter time, watchdog timeout window (TWOP–TWOL), and RESET delay. Without CD, the watchdog remains disabled, NMI response becomes undefined, and the reset sequence fails to meet automotive timing requirements. Typical values range from 10 nF to 100 nF depending on desired timeout duration.
How does the L9777C13TR handle battery voltage transients up to 40 V?
The L9777C13TR implements Option C's internal protection architecture: VI and VDD pins withstand 40 V transients due to integrated series diode and PMOS structure. VDD regulator remains functional during such events, and VDD_LOW continues monitoring relative to VCC. The device does not require external clamping components for ISO 7637-2 Pulse 5a compliance in 24 V systems.
Is the RADJ pin required for basic operation of the L9777C13TR?
No - RADJ is optional. When left unconnected or tied to GND, the internal undervoltage threshold defaults to 0.94 × VCC (typical). External resistor divider on RADJ only enables adjustment between 0.7×VCC and 0.96×VCC, useful for extending operation during cold-cranking or matching specific MCU reset thresholds. Basic regulation and reset functions operate fully without RADJ.
L9777C13TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- 12-LSOP (0.154", 3.90mm Width) Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Configuration:
- Positive
- Output Type:
- Adjustable
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 31V
- Voltage - Output (Min/Fixed):
- 4.9V
- Voltage - Output (Max):
- 5.1V
- Voltage Dropout (Max):
- 1.5V @ 50mA
- Current - Output:
- 600mA
- Current - Quiescent (Iq):
- 700 µA
- Current - Supply (Max):
- -
- PSRR:
- 55dB (100Hz)
- Control Features:
- -
- Protection Features:
- Over Current, Over Temperature, Short Circuit
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- PowerSSO-12
L9777C13TR FAQ
1.How can I place an order for L9777C13TR through Aetrix?
Please submit a Request for Quotation (RFQ) for L9777C13TR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for L9777C13TR reliable?
The price and inventory of L9777C13TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L9777C13TR is usually 5 days.
3.What payment methods are accepted for L9777C13TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L9777C13TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for L9777C13TR?
L9777C13TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your L9777C13TR order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for L9777C13TR?
For technical support, including L9777C13TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L9777C13TR requirements.
6.How does Aetrix verify that L9777C13TR is sourced from the original manufacturer or authorized distributors?
All L9777C13TR products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that L9777C13TR meets industry standards.
7.What is the process for return or replacement of L9777C13TR?
All L9777C13TR units undergo pre-shipment inspection (PSI). If there is an issue with L9777C13TR, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The L9777C13TR part is unused and in its original packaging.
Return procedure for L9777C13TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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